I read this around 25 years ago. I remember very, very little about the story. Glimpses mostly.
What I do remember, in the beginning, a female character, maybe a scientist, meets a male character who (maybe) lived on/came from the dangerous planet. That male character is presented in the book as being very strong and big in size, a lot due to the fact that the conditions on that dangerous planet are harsh (higher gravity than on Earth, dangerous alien environment etc.) They eventually go on a journey for some mission. Inter alia, during the mission the woman's friend who comes with them, is killed by his head being ripped off.
There is a distinct aspect I remember. The strong big guy has (as well as anyone from his kind, who live on that dangerous planet) a particular way to use the gun. Specifically, the gun can pop automatically from the holster in the hand, and for a normal human eye, the movement would be instantaneous, as if the gun "magically" appeared in the hand. The people who are guy's kind developed that holster-gun system (the gun might be connected to the holster via a wire, but I am not sure at this moment that I remember correctly) to be able to shoot extremely fast on the dangerous planet.